The history of the Welsh sees carries us back to the early days of British Christianity. When the Saxon tribes swept over the land they destroyed the churches and monasteries, and drove the British west-ward, who found a refuge in the hills of Wales, in Devon, Cornwall and Somerset, and in the regions north of the Mersey, and there the British Church continued to exist and flourish, though the rest of England was submerged in the flood of Paganism. When Augustine came he found in these parts of England a church governed by its bishops, who did not recognise the authority of the Pope, and whose customs differed somewhat from those of Rome. He summoned them to a conference, which was held at a place called "Augustine's oak," where by his haughty demeanour he offended the representatives of the ancient native church, who refused to abandon their accustomed usages, especially in the matter of the time for observing Easter and the forms of the tonsure.

In Roman times Caerleon was a see, which seems to have embraced the whole of Wales. Then there were five principalities, each of which had a bishop. These were Bangor, Llanelwy (St. Asaph's), St. David's, Llandaff and Llanbadarn, afterwards incorporated with St. David's. Judging from the number of the names of saints which occur in Welsh nomenclature, we may conclude that the Welsh Church was famous for its zeal and activity and for the holiness of its members. It sent preachers and missionaries to Ireland, to Brittany, and Cornwall and Devon. It founded colleges and schools, and the great Celtic Church assisted in the conversion of the Northern Saxons of England, and even sent missionaries to the Continent. By degrees the British Church became merged in the English, founded by Augustine, and with the appointment of Norman prelates in the time of the Conqueror, any lingering survivals of ancient customs and usages were lost, and the unity of the church fully established.

The earliest bishop of the See of Llandaff whose name is recorded was St. Dubricius. He is reputed to have founded the see in 612 A.D., but his successor, St. Teilo, seems to have had the chief credit of accomplishing the work. Of course the mythical King Lucius is dragged in as the earliest founder, but we have always neglected the legends connected with him. Of the early Welsh bishops we have no sure information, though there is the famous Book of Llandaff, which does not afford much certain knowledge, and is full of inaccuracies. Bishop Urban was consecrated in 1107, conveyed here the relics of Dubricius, and began to rebuild his Cathedral, for which an indulgence was granted by the Archbishop of Canterbury to all who should assist him in the work. Possibly it was finished in his time, but we have no certain information, and the stones of the church can alone tell the story of its building. During the thirteenth century the western part of the nave was erected, and also the chapter-house, which is of Early English design. During the Decorated period the Lady Chapel was added and the presbytery rebuilt, and the walls of the aisles also renewed. The north-west tower was erected in the Perpendicular period by the Earl of Pembroke, uncle of Henry VII. Thus the church was completed. It was not a very beautiful structure, and time has dealt hardly with it. The spoilers at the Reformation plundered it; decay and desolation reigned in the deserted "long-drawn aisle." Some bishops seem to have attempted to do something, but the whole condition of the church was deplorable. Then the troubles of the Civil War period fell upon this Job-like structure, and in spite of some attempts to improve its condition at the Restoration, and at subsequent periods, it still remained in a ruinous state. Then in 1723, when the taste for Italian models was rampant, the authorities erected an Italian temple-like building at the east end. This happily has been entirely removed during the restorations, which commenced in the middle of the last century, when the church was completely renovated, and all the old portions which had escaped the action of time, or the barbarous efforts of the followers of Christopher Wren, restored to their original state. The work was finished in 1869. Although much of the church is new, on close inspection we can discover some ancient work that lacks not interest.

The West Front is very beautiful. The doorway is a fine example of Early English work. It consists of a round arch, with two sub-arches, and in the tympanum there is an episcopal figure, probably that of St. Dubricius. The shafts at the sides of the doorway are Early English. Above them are lancet windows, and in the gable a figure of our Lord in glory. The cross above the gable is modern. The front is flanked on each side by two towers. The north-west tower is Perpendicular, the work of Jasper Tudor, Earl of Pembroke, uncle of Henry VII.; the south-west tower is modern.

The Nave consists of five bays, and is of Early English design. There is no triforium. The clerestory windows are lancets, and a passage runs in front of them. We notice the graceful foliage on the pier capitals, of Late Early English design, when the stiff-leaved foliage was giving way to the more natural foliage of the Decorated period. The aisles were rebuilt in the Late Decorated period, but two Norman doorways on the north and south sides were preserved. The choir is of the same character as the nave, but in the presbytery we see some of the Norman work of Urban's church, mixed with that of the Decorated period. Here stood the Italian temple, until happily this monstrosity was removed. The clerestory was destroyed when the temple was erected, but in the restoration of Sir Gilbert Scott it was rebuilt. On the south side we notice the curious blending of the Norman with the Decorated work. One of the most striking features of this Cathedral is the Late Norman arch at the east end. It is very richly ornamented, and has four orders, being adorned with zigzag, roll, and a curious row of flower-like circles. The reredos is modern, and has some fine paintings by Rosetti. The sedilia are modern.

The Lady Chapel has a stone vault, the ribs rising from Purbeck marble shafts. The windows are of good design, having two lights with a circle in the head. The east window is modern. The chapter-house is Early English, and is almost unique in having a square plan with a central pier.

Few of the monuments possess much interest. We notice that of St. Dubricius; a brass memorial of Bishop Copleston (1849); Bishop William de Bruce (1287); Bishop St. Teilo; Bishop Bromfield (1393); Bishop Marshall (1496), a skeleton figure of the memento mori type; Sir David Matthew, standard-bearer to Edward IV. (1461); Sir William Matthew; Lady Audley. The old reredos discovered during the restoration has been placed in the north aisle of the choir.